Abstract
Purpose:
Oculocutaneous albinism (OCA) is an autosomal recessive disorder. The most common type OCA1 and OCA2 are caused by homozygous or compound heterozygous mutations in the tyrosinase gene (TYR) and OCA2 gene, respectively.This study was to evaluate the molecular basis of oculocutaneous albinism in four Chinese families.
Methods:
We examined four non-consanguineous OCA families. The TYR and OCA2 genes of all individuals were amplified by polymerase chain reaction (PCR), sequenced and compared with a reference database.
Results:
Four patients, diagnosed as oculocutaneous albinism, presented with milky skin, white or light brown hair and nystagmus. Genetic analyses demonstrated that patient 1 was compound heterozygote for c.1037-7T.A, c.1037-10_11delTT and c.1114delG of TYR gene; patient 2 was heterozygote for c.593C>T and c.1426A>G of OCA2 gene, patient 3 and 4 was compound heterozygote of TYR gene (c.549_510delGT and c.896G>A, c.832C>T and c.985T>C). The heterozygous c.549_510delGT and c.1114delG alleles of TYR gene were two novel mutations. Interestingly, unaffected members in these pedigrees who carried c.1114delG of TYR gene or c.1426A>G of OCA2 gene presented with blond/brown hair and pale skin, but no ocular disorders when they were born, pigment was accumulated over time and with sun exposure.
Conclusions:
This study expands the mutation spectrum of oculocutaneous albinism. It is the first report that c.549_510delGT and c.1114delG of TYR gene were associated with OCA. The two mutations (c.1114delG of TYR gene and c.1426A>G of OCA2 gene) may responsible for part of clinical manifests of OCA.